喀斯特常绿落叶阔叶林凋落物产量动态及影响因素  

Dynamics of litter production and its determinants in a subtropical mixedevergreen and deciduous broad-leaved forest in a karst ecosystem

作　　者：熊松 淦江 谢彦军 邓晰朝 覃国乐 彭晚霞[1,2] 曾馥平[1,2] 占志立 谭卫宁 黄国勤[5] 杜虎[1,2] Song Xiong;Jiang Gan;Yanjun Xie;Xizhao Deng;Guole Qin;Wanxia Peng;Fuping Zeng;Zhili Zhan;WeiningTan;Guoqin Huang;Hu Duola(Key Laboratory of Agro-ecological Processes in Subtropical Region,Public Technology Center,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 410125,China;Huanjiang Observation and Research Station for Karst Ecosystems,Chinese Academy of Sciences,Huanjiang,Guangxi 547100,China;College of Chemistry and Biology Engineering,Hechi University,Yizhou,Guangxi 546300,China;Administrative Centre of Guangxi Mulun National Nature Reserve,Huanjiang,Guangxi 547100,China;Center for Ecological Science,Jiangxi Agricultural University,Nanchang 330045,China)

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所公共技术中心,长沙410125 [2]中国科学院环江喀斯特生态系统观测研究站,广西环江547100 [3]河池学院化学与生物工程学院,广西宜州546300 [4]广西木论国家级自然保护区管理中心,广西环江547100 [5]江西农业大学生态科学研究中心,南昌330045

出　　处：《生物多样性》2024年第12期120-130,共11页Biodiversity Science

基　　金：广西自然科学基金(2023GXNSFAA026109);国家自然科学基金(42071073,42277245);国家重点研发计划项目(2022YFF1300703);中国科学院青年创新促进会项目(2021366)。

摘　　要：凋落物作为森林生态系统的重要组成部分,在生态系统物质循环、能量流动和养分平衡方面发挥着重要作用。为探究中亚热带喀斯特森林凋落物产量的年际动态变化及其影响因素,本研究基于广西木论喀斯特常绿落叶阔叶林25ha森林动态监测样地151个凋落物收集器的布置,通过连续60个月的数据积累,分析了凋落物组成、时间动态及影响因素。结果表明:中亚热带喀斯特森林凋落物年均产量为5,946.55±77.27kg/ha,年际差异明显,各组分所占比例依次为叶(63.26%)>杂物(24.89%)>枝(12.79%)。总凋落物量与叶凋落量季节变化规律相似,均呈双峰型,在春季3–4月和秋季9–10月出现峰值;枝凋落量月际动态为单峰型,凋落高峰出现在秋季10月;杂物凋落量月际动态也为双峰型,两个峰值分别出现在春季5月和秋季10月。凋落物收集器5 m邻域范围内,物种多样性、凹凸度、胸高断面积是喀斯特森林凋落物产量的主要驱动因素,物种多样性、胸高断面积、凹凸度对凋落物总量有直接影响,而坡度通过物种多样性间接影响凋落物总量。5年连续监测结果表明,喀斯特常绿落叶阔叶混交林凋落物量节律性差异明显,生物和地形因子共同影响着凋落物量的空间变异。Aims:Litter constitutes a crucial component of forest ecosystems,playing significant roles in biogeochemical cycling,energy flow,and nutrient balance.Nevertheless,understanding the mechanisms by which biotic and abiotic factors influence litter production in heterogeneous natural forest ecosystems remains contentious.This study aims to investigate the long-term dynamics and influential factors affecting litter production in karst forests within subtropical regions.Methods:In this study,we set up 151 litter traps,and collected litter monthly from 2018 to 2022 in a 25-ha karst evergreen and deciduous broad-leaved mixed forest dynamics plot in the Mulun National Nature Reserve,Guangxi Province.All litter in each trap was dried,classified and weighed.Results:The average annual litter production in karst forests was 5,946.55±77.27 kg/ha,with significant inter-annual variability.The proportion of each litter component ranked as follows:leaves(63.26%)>debris(24.89%)>twigs(12.79%).Seasonal patterns for total litter and leaf litter production were similar,displaying a bimodal trend with peaks in spring(March-April)and fall(September-October).Monthly dynamics of branch litter followed a unimodal pattern,peaking in autumn(around October),while debris showed a bimodal pattern with peaks in spring(May)and fall(October),respectively.The species diversity,convexity,mean diameter at breast height(DBH),were the main driving factors of litter production within a 5 m radius neighborhood around the traps.The results of the structural equation model indicated that the species diversity,DBH,and convexity have a direct influence on the total litter production,while slope had an indirect influence on the total litter production through altering species diversity.Conclusion:Five years of continuous monitoring have revealed significant seasonal variations in litter production within the karst evergreen and deciduous broad-leaved mixed forest.Both biotic and topographic factors collectively affected the spatial variability of litter produ

关 键 词：凋落物 生物多样性 地形 喀斯特生态系统 木论 

分 类 号：S71[农业科学—林学]